3,137 research outputs found
Coherent-state quantization of constrained fermion systems
The quantization of systems with first- and second-class constraints within
the coherent-state path-integral approach is extended to quantum systems with
fermionic degrees of freedom. As in the bosonic case the importance of
path-integral measures for Lagrange multipliers, which in this case are in
general expected to be elements of a Grassmann algebra, is emphasized. Several
examples with first- and second-class constraints are discussed.Comment: LaTeX 2e, Springer macro pljour2, 11 pages, to appear in Z. Phys.
Roll tracking effects of G-vector tilt and various types of motion washout
In a dogfight scenario, the task was to follow the target's roll angle while suppressing gust disturbances. All subjects adopted the same behavioral strategies in following the target while suppressing the gusts, and the MFP-fitted math model response was generally within one data symbol width. The results include the following: (1) comparisons of full roll motion (both with and without the spurious gravity tilt cue) with the static case. These motion cues help suppress disturbances with little net effect on the visual performance. Tilt cues were clearly used by the pilots but gave only small improvement in tracking errors. (2) The optimum washout (in terms of performance close to real world, similar behavioral parameters, significant motion attenuation (60 percent), and acceptable motion fidelity) was the combined attenuation and first-order washout. (3) Various trends in parameters across the motion conditions were apparent, and are discussed with respect to a comprehensive model for predicting adaptation to various roll motion cues
Hohenberg-Kohn theorem for the lowest-energy resonance of unbound systems
We show that under well-defined conditions the Hohenberg-Kohn theorem (HKT)
can be extended to the lowest-energy resonance of unbound systems. Using the
Gel'fand Levitan theorem, the extended version of the HKT can also be applied
to systems that support a finite number of bound states. The extended version
of the HKT provides an adequate framework to carry out DFT calculations of
negative electron affinities.Comment: 4 pages, 3 figure
Coherent states for polynomial su(1,1) algebra and a conditionally solvable system
In a previous paper [{\it J. Phys. A: Math. Theor.} {\bf 40} (2007) 11105],
we constructed a class of coherent states for a polynomially deformed
algebra. In this paper, we first prepare the discrete representations of the
nonlinearly deformed algebra. Then we extend the previous procedure
to construct a discrete class of coherent states for a polynomial su(1,1)
algebra which contains the Barut-Girardello set and the Perelomov set of the
SU(1,1) coherent states as special cases. We also construct coherent states for
the cubic algebra related to the conditionally solvable radial oscillator
problem.Comment: 2 figure
Classical Supersymmetric Mechanics
We analyse a supersymmetric mechanical model derived from (1+1)-dimensional
field theory with Yukawa interaction, assuming that all physical variables take
their values in a Grassmann algebra B. Utilizing the symmetries of the model we
demonstrate how for a certain class of potentials the equations of motion can
be solved completely for any B. In a second approach we suppose that the
Grassmann algebra is finitely generated, decompose the dynamical variables into
real components and devise a layer-by-layer strategy to solve the equations of
motion for arbitrary potential. We examine the possible types of motion for
both bosonic and fermionic quantities and show how symmetries relate the former
to the latter in a geometrical way. In particular, we investigate oscillatory
motion, applying results of Floquet theory, in order to elucidate the role that
energy variations of the lower order quantities play in determining the
quantities of higher order in B.Comment: 29 pages, 2 figures, submitted to Annals of Physic
More on coupling coefficients for the most degenerate representations of SO(n)
We present explicit closed-form expressions for the general group-theoretical
factor appearing in the alpha-topology of a high-temperature expansion of
SO(n)-symmetric lattice models. This object, which is closely related to
6j-symbols for the most degenerate representation of SO(n), is discussed in
detail.Comment: 9 pages including 1 table, uses IOP macros Update of Introduction and
Discussion, References adde
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